Can I still ask RMA for help if I have fixed my phone before?

Hello everyone,

I'm a new fan of doing DIY repairment.

Today I went to UbreakIFix for a battery replacement, and they mentioned that because I fixed my screen on my own before, which means I have opened the cover on my own, they won't offer me a warranty.

So my question is:

In my case mentioned above, can I ask RMA for buying/replacing the OEM battery?

The reason I went to UbreakIFix is that I can't find a real OEM battery on amazon/ebay... So I want to know if I can get the help from Google or somewhere.

Thanks so much!

Leo